In the past, plasma surface treatments have widely used for the purposes of cleaning foreign substances such as organic materials on an object to be treated, etching or peeling resists, improving adhesion of organic films, reducing metal oxides, forming films, pretreatments for plating and coating, and surface modifications of various kinds of materials and parts.
For example, Japanese Patent Early Publication [kokai] No. 11-335868 discloses performing a surface treatment to objects with a plasma generated in a discharge space between a pair of electrodes by applying a voltage between the electrodes, while supplying a plasma generation gas into the discharge space. In this plasma surface treatment, since the plasma or activated species of the plasma is ejected from a single nozzle, and the objects are plasma treated, while being conveyed in a direction orthogonal to the ejecting direction, there is a problem that variations in treatment effect on the objects easily occur.
In addition, Japanese Patent Early Publication [kokai] No. 4-358076 discloses that a treatment area is increased by using a plasma or activated species of the plasma, which is generated by use of a reaction vessel with dielectric coated electrodes obtained by placing a solid dielectric material on surfaces of a plurality of electrodes disposed in parallel to each other. According to this technique, it is possible to perform a surface treatment to a large area of the object at a time. However, there is still plenty of room for improvement in the view of providing the plasma or the activated species of the plasma to the entire treatment area by a uniform gas flow. In addition, such a large-area plasma treatment has another problem that a large amount of consumption of the gas leads to an increase in running cost.
In addition, with respect to the object such as a glass for liquid crystal panel, it is desired to further increase the treatment area in the future. To cope with various kinds of objects, it is needed to increase the level of freedom in designing the apparatus.